Senior Notes and Loans Payable - Schedule of Senior Notes (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2017	May 31, 2016
Debt Instrument [Line Items]
Discount and deferred loan costs	$ (16,015)	$ (21,091)
Total	$ 1,033,985	$ 1,410,804
Senior Notes | 4.375% Senior Notes due June 15, 2019
Debt Instrument [Line Items]
Interest rate on senior note (percent)	4.375%	4.375%
Long-term debt, gross	$ 0	$ 381,895
Senior Notes | 4.875% Senior Notes due July 1, 2021
Debt Instrument [Line Items]
Interest rate on senior note (percent)	4.875%	4.875%		4.875%
Long-term debt, gross	$ 300,000	$ 300,000
Senior Notes | 5.875% Senior Notes due June 15, 2024
Debt Instrument [Line Items]
Interest rate on senior note (percent)	5.875%	5.875%
Long-term debt, gross	$ 450,000	$ 450,000
Senior Notes | 5.250% Senior Notes due June 1, 2027
Debt Instrument [Line Items]
Interest rate on senior note (percent)	5.25%	5.25%	5.25%
Long-term debt, gross	$ 300,000	$ 300,000